Papers by Alberto Colombo
Revista PesquisAgro, Apr 7, 2020
Revista Brasileira De Ciencia Do Solo, Aug 31, 2017
The scarcity of field data to develop soil maps through a pedological survey is one of the main l... more The scarcity of field data to develop soil maps through a pedological survey is one of the main limitations to using distributed hydrological models, especially in small and medium-sized watersheds. The aim of this study was to compare a distributed hydrological model prediction to a soil map based on a pedological survey and a moisture zone map obtained using the Height Above the Nearest Drainage -HAND model. The Distributed Hydrology Soil Vegetation Model -DHSVM, which is a physically-based and distributed hydrological model, was applied to a mountainous watershed, located in the region of the Mantiqueira Range in the south of Minas Gerais in southeastern Brazil, and was compared to both maps mentioned above, taking the soil map developed by the pedological survey as a reference. Daily weather and streamflow data-sets were used for DHSVM calibration and validation using the two different maps (soil and moisture zone maps) as inputs. In both simulations, the DHSVM performed well, with outputs indicating a good relationship between topographical and hydrological characteristics from the two types of maps. Thus, the moisture zone map obtained by the HAND model can also be successfully used in distributed hydrological modeling, especially for mountainous regions in southeastern Brazil.
Engenharia Agricola, Aug 1, 2020
This work aimed to simulate the water distribution of traveler gun irrigation, working with asymm... more This work aimed to simulate the water distribution of traveler gun irrigation, working with asymmetrical wetted angles and in windy conditions. In the simulations of a sprinkler with uniform radial profile, the following were considered: i) wetted angles between 180 and 330º; ii) wetted angle asymmetries from 0 to 90º; iii) wind speeds from 0 to 4.5 m s-1 ; and iv) wind direction of 0, 45, and 90º. Christiansen uniformity coefficients (CU) were calculated for strip widths from 30 to 100% of the sprinkler wetted diameter (WD). Regardless of the wetted angle adjustment, irrigations under wind speeds of 4.5 m s-1 should be avoided and strip spacings of less than 50% WD provide high CU for wind speeds up to 3.0 m s-1. For any wind conditions, asymmetries in the wetted angle led to a reduction in CU for a wetted angle of 210º. In the range of wetted angle from 270 to 330º, asymmetric adjustments of up to 20º provided a higher CU than 80% for a wind speed of 3 m s-1 and directions diagonal and perpendicular to the travel path associated with strip spacings between 60 to 70% WD, which are the spacings recommended by manufacturers of traveler irrigation machines.
Vegetative development of Jatropha curcas in response to irrigation and application of OMM-Tech
Central theme, technology for all: sharing the knowledge for development. Proceedings of the International Conference of Agricultural Engineering, XXXVII Brazilian Congress of Agricultural Engineering, International Livestock Environment Symposium - ILES VIII, Iguassu Falls City, Brazil, 31st Aug..., 2008
Revista Brasileira de Engenharia de Biossistemas
Pressure demand of a center-pivot can be controlled by variable frequency drives during irrigatio... more Pressure demand of a center-pivot can be controlled by variable frequency drives during irrigation system operations, leading to a rational use of electrical energy. However, numerous studies encountered problems due to the lack of field data to perform the simulations. The objective of this study was to simulate the reduction of the average value of the active electrical power required to drive the pumping unit of a center-pivot irrigation system by controlling the rotational speed through a frequency inverter. The simulation was conducted considering a complete rotation of the lateral line of a central pivot, installed in an area of 70-ha, in the municipality of Formiga-MG. The simulation demonstrated the possibility of reducing the active electrical power required for the pivot pump by 18%, from an average of 131 to 107 kW. For 1300 pumping hours per year, the investment's payback time would be two and four years for the highest (R$ 0.48 kWh-1) and lowest energy cost (R$ 0.32...
Engenharia Sanitaria e Ambiental
Rainfall simulators are an important tool in many areas of geosciences. The authors of most of th... more Rainfall simulators are an important tool in many areas of geosciences. The authors of most of the studies published with rainfall simulators try to get the most uniform distribution of precipitation as possible. However, since this is very difficult, indexes are used to assess the greater or lesser uniformity of precipitation in the plot area under study. One of the most used indexes is the Christiansen uniformity coefficient. In this work, changes in the geometry of the wetted area of the plot were analyzed to improve the uniformity of precipitation. This was evaluated through the intensity of precipitation and Christiansen uniformity coefficient in the wet area. The tests were carried out using two models of spray nozzles and different operating pressures. The initial plot geometry was 0.7 x 1.0 m (0.7 m2). The Christiansen uniformity coefficient results were classified as low, while the best performance in terms of precipitation uniformity was obtained at a pressure of 48.3 kPa....
Ajuste numérico de parâmetros de transporte de solutos no solo Breakthrough curves
A distribuicao espacial da carga de pressao ao longo dos 432,6m de comprimento de uma linha later... more A distribuicao espacial da carga de pressao ao longo dos 432,6m de comprimento de uma linha lateral de um pivo central foi determinada a partir de valores medidos, na entrada e na extremidade da linha lateral, e combinados com dados de altitude proveniente de uma imagem SRTM do rastro das oito torres de sustentacao da linha lateral. Para fins de validacao da estimativa da distribuicao espacial da carga de pressao na linha lateral movel, em 18 diferentes posicoes angulares, foram medidos valores de carga de pressao em seis pontos distintos do seu comprimento. Diferencas significativas, ao nivel de 5% do teste de medias “t de student”, foram observadas quando valores de carga de pressao estimados com dados de altitude do SRTM foram comparados com os valores medidos em campo. Apos a confeccao de mapas tematicos verificou-se coincidencia no posicionamento das regioes de ocorrencia dos valores mais elevados, como tambem dos menores valores de carga de pressao. O estudo demonstrou que o u...
Water, 2019
Pumping systems are the largest energy consumers in center pivot irrigation systems. One action t... more Pumping systems are the largest energy consumers in center pivot irrigation systems. One action to reduce energy consumption is to adjust the pumping pressure to that which is strictly needed by using variable speed drives (VSDs). The objective of this study was to determine the feasibility of including VSDs in pumping systems that feed center pivot systems operating in an area with variable topography. The VSPM (Variable Speed Pivot Model) was developed to perform hydraulic and energy analyses of center pivot systems using the EPANET hydraulics engine. This tool is able to determine the elevation of each tower for each position of the center pivot using any type of digital elevation model. It is also capable of simulating, in an accurate manner, the performance of the center pivot controlled with a VSD. The tool was applied to a real case study, located in Albacete, Spain. The results show a reduction in energy consumption of 12.2%, with specific energy consumptions of 0.214 and 0....
Ciência e Agrotecnologia, 2016
Climate change impacts need to be considered in water resource planning. This work aims to study ... more Climate change impacts need to be considered in water resource planning. This work aims to study of the impacts climate change on Lavrinha headwater watershed, located in the Mantiqueira Range, southeastern Brazil. The impacts from climate change (RCP 8.5 scenario) in the Lavrinha watershed runoff were analyzed based on the "Distributed Hydrology Soil Vegetation Model" (DHSVM), forced with the climate simulated for this future climate change scenario. These simulations, in turn, were generated by the Eta regional climate model coupled to Global Climate Model (GCM) HadGEM2-ES for the 2011-2040, 2041-2070 and 2071-2099 periods. The results of this study showed that the runoff is very sensitive to rising temperatures and reduced precipitation, both projected for the RCP 8.5 scenario. The hydrological simulation projected a reduction in the monthly streamflow between 20 and 77% over the twenty-first century (2011-2099), corresponding to drastic reductions in the runoff behavio...
Revista de Tecnologia da Informação e Comunicação, 2014
Resumo-Este artigo descreve uma aplicação de controladores lógico programáveis (CLP) em conjunto ... more Resumo-Este artigo descreve uma aplicação de controladores lógico programáveis (CLP) em conjunto com inversores de frequência em sistemas de irrigação por pivô central com o objetivo de aumentar a eficiência do uso da energia elétrica, utilizando redes ZigBee (802.15.4), Modbus-RTU e Compobus R , para comunicação entre os equipamentos e sensores. Sabe-se que o aumento do consumo da energia elétrica no meio rural está diretamente associado ao desenvolvimento tecnológico da agricultura. Portanto, o emprego de modernas técnicas que otimizem o uso racional da energia elétricaé fundamental em todos asáreas de conhecimento. O experimento foi realizado no campus da Universidade Federal de Lavras (UFLA), dentro do programa de doutorado em Engenharia Agrícola, nos anos de 2008-2009, tendo apoio do CNPq e FAPEMIG. São apresentados a fundamentação, metodologia e resultados alcançados na execução do projeto implementado.
Anais do IV Inovagri International Meeting - 2017, 2017
RESUMO: O uso de inversores de frequência para aumento da eficiência energética de equipamentos d... more RESUMO: O uso de inversores de frequência para aumento da eficiência energética de equipamentos do tipo pivô central, sem prejuízo da sua uniformidade de aplicação da água, só é alcançado com o conhecimento adequado do comportamento do ponto de mínima pressão da linha lateral em toda a área irrigada. O objetivo deste trabalho é descrever uma estratégia que permite incorporar o Software EPANET 2.0 na determinação precisa do valor e da posição do ponto de pressão mínima da linha lateral de um pivô central. O EPANET 2.0 foi utilizado para simular a distribuição espacial da pressão de um pivô central de 58,8ha, em 18 diferentes posições da linha lateral. Nestas simulações, foram consideradas características da curva da bomba, das tubulações, das válvulas reguladoras de pressão, dos emissores e informações topográficas. Neste sistema, quando a velocidade de rotação da bomba é mantida constante, a carga de pressão mínima da lateral assume valores que bem superiores ao mínimo necessário (13m), variam entre 24,1 e 34,5m, em pontos localizados entre 0 e 428,67m do ponto do pivô. Estes resultados ilustram a adequação do uso do EPANET 2.0 na simulação hidráulica de sistemas de irrigação do tipo pivô central. PALAVRAS-CHAVE: economia de energia, inversor de frequência, bombeamento com velocidade variável.
Vegetative development of Jatropha curcas in response to irrigation and application of OMM-Tech
CATENA, 2016
The Atlantic Forest is one of the most important forest biomes in Brazil, and this biome continue... more The Atlantic Forest is one of the most important forest biomes in Brazil, and this biome continues to disappear. This study looked at simulated and observed hydrological components in a small watershed containing fragments of the Atlantic Forest. The performance of the Distributed Hydrology Soil Vegetation Model (DHSVM) and the effects of possible land cover change scenarios in the Lavrinha Watershed, in the Mantiqueira Range, Minas Gerais State, Brazil, were analyzed. The model was calibrated and validated using four years of continuous hydro-climate data sets, and the simulated daily and monthly streamflow showed acceptable agreement with the observed. A comparison of hypothetical land cover change scenarios showed that deforestation in the Atlantic Forest biome leads to increases in monthly soil moisture (by 5%), overland flow (by 33%) and total runoff (by 22%), with a corresponding decrease in interception (by 71%), evapotranspiration (by 30%) and water table depth (by 10%). These changes in land surface hydrology resulted in an increase in daily high and low streamflows (by 17% and 25%), with the opposite occurring when pasture was converted to Atlantic Forest. The results also show that the hydrology of a headwater tropical watershed is characterized by seasonal variability in rainfall and land cover changes and that there are connections among the topography, land cover, soil types and wet and dry seasons that maintain the spatial distribution of the hydrologic components in the watershed.
The aim of this study was to evaluate criteria for irrigation and planting densities best suited ... more The aim of this study was to evaluate criteria for irrigation and planting densities best suited to coffee growing to maximize yield. The experiment was conducted in an area of the Department of Agriculture, Federal University of Lavras, Minas Gerais, Brazil, in a randomized complete block design with split-plots and four replications. Planting was carried outusing healthy coffee seedlings of the Ruby MG-1192 cultivar. It was observed that the use of irrigation provided for significant increases in processed coffee yield in high density planting from 10,000 to 20,000 plants ha-1. Irrigations based on tensions from 60 kPa to 100 kPa are sufficient to meet the water requirements of coffee in dense plantings, but the increase in the number of plants from 10,000 to 20,000 compromises the sustainability of the crop through the disproportionate increase in waterconsumption for irrigation, with small increases in yield. For the irrigation tension of 60 kPa, the relative increase in yield o...
The aim of this study was to evaluate criteria for irrigation and planting densities best suited ... more The aim of this study was to evaluate criteria for irrigation and planting densities best suited to coffee growing to maximize yield. The experiment was conducted in an area of the
Ambiente e Agua - An Interdisciplinary Journal of Applied Science, 2021
This study assessed the impact of climate change on monthly streamflow in the Verde River Basin, ... more This study assessed the impact of climate change on monthly streamflow in the Verde River Basin, located in the Grande River Basin headwater. For this purpose, the SWAT and VIC hydrological models were used to simulate the monthly streamflow under RCP4.5 and RCP8.5 scenarios, obtained by Regional Climate Models Eta-HadGEM2-ES, Eta-CanESM2 and Eta-MIROC5 in the baseline period (1961-2005) and three time-slice (2011-2040, 2041-2070, and 2071-2099) inputs. At the end of the century, the Eta-HadGEM2-ES showed larger decrease of precipitation in both radiative scenarios, with an annual reduction of 17.4 (RCP4.5) and 32.3% (RCP8.5), while the Eta-CanESM2 indicated major warming, with an annual increase of 4.7 and 10.2°C under RCP4.5 and RCP8.5, respectively. As well as precipitation changes, the Eta-HadGEM2-ES also showed greater impacts on streamflow under RCP4.5 for the first time-slice (2011-2040), with an annual decrease of 58.0% for both hydrological models, and for the RCP8.5 scenar...
Engenharia Agrícola, 2018
This study aimed to evaluate the energy efficiency of a center pivot irrigation system operating ... more This study aimed to evaluate the energy efficiency of a center pivot irrigation system operating in a terrain of variable topography. Values of Pumping Energy Efficiency (PEE), Supply Energy Efficiency (SEE), Global Energy Efficiency (GEE) and Specific Energy (Es in kWh m-3) computed at 18 different angular positions of the lateral line were used as energy efficiency indicators. An ultrasonic flow meter, digital pressure transducers and a power quality analyzer were used in order to evaluate hydraulic (total system flow-Q and total dynamic head-TDH) and electrical parameters (active electrical power-AEP) of the center pivot pumping unit that were required for evaluating the selected energy efficiency indictors. Topographic elevations of the water source, the pumping unit and of the center lateral line were also determined. For the center pivot lateral line, it was necessary to determine, at the 18 angular positions considered, the altitude of the track of each center pivot support tower. Results indicated that currently, even after more than 10000h of use, the center pivot system operates with satisfactory energy efficiency, as indicated by an average GEE value equal to 42.5%, that is classified as "good". Statistical analysis indicated that the topographic disposition of the center pivot lateral line, as characterized by a uphill or downhill disposition, resulted on different PEE, SEE and GEE values, while the average Es value (0.42 kWh m-3) was not affected by the lateral line disposition.
American Journal of Climate Change, 2018
Climate change is one of the greatest issues for human society. The objective of this study is to... more Climate change is one of the greatest issues for human society. The objective of this study is to assess the impacts of future climate change on seasonal average discharge and monthly water budget in a small headwater catchment, located on the Grande River basin, in Minas Gerais, Brazil. The assessment is carried out using the hydrology model, DHSVM. The atmospheric forcing to drive the Distributed Hydrology-Soil-Vegetation Model (DHSVM) is derived from the downscaling of the HadGEM2-ES projections by the Eta Regional Climate Model, at 5-km high resolution. The projections assume the RCP4.5 and RCP8.5 IPCC AR5 emission scenarios. Baseline period was taken between 1961 and 1990. The projections are assessed in three time slices (2011-2040, 2041-2070 and 2071-2099). The climate change is assessed in time slices of 30 years and in comparison against the baseline period to evaluate the hydrological changes in the catchment. The results showed differences in the hydrological behavior between the emission scenarios and though time slices. Reductions in the magnitude of the seasonal average discharge and monthly water budget may alter the water availability. Under the RCP4.5 scenario, results show greater reductions in the water availability in the first time slice, whereas under RCP8.5 scenario greater reductions are indicated in the third time slice.
IRRIGA, 2018
PERDAS DE ÁGUA POR EVAPORAÇÃO E ARRASTE NA IRRIGAÇÃO POR ASPERSÃO NAS CONDIÇÕES CLIMÁTICAS DE LAV... more PERDAS DE ÁGUA POR EVAPORAÇÃO E ARRASTE NA IRRIGAÇÃO POR ASPERSÃO NAS CONDIÇÕES CLIMÁTICAS DE LAVRAS-MG, UTILIZANDO ASPERSORES DE TAMANHO MÉDIO[1] Samuel Beskow; Alberto Colombo; Geraldo Magela Pereira; José Henrique da Silva Taveira; Célio Moreira RicardoDepartamento de Engenharia, Universidade Federal de Lavras, Lavras, MG, samuelbeskow@terra.com.br 1 RESUMO O objetivo deste trabalho foi determinar as perdas de água por evaporação e arraste durante ensaios de campo com um único aspersor e também com laterais de aspersores, sob várias condições climáticas, usando quatro modelos de aspersores, operando em três níveis de pressão. Quatro diferentes modelos de aspersores, representando diferentes combinações de diâmetro de bocal e ângulo de jato, foram usados: 1 - Agropolo NY-7 (4,6 mm x 4 mm e 7º); 2 - Agropolo NY-12 (3,5 mm e 12º); 3 - Naan (3,0 mm e 12º); e 4 - Agropolo NY-25 (2,8 mm x 2,5 mm e 25º). Testes de campo mostraram que as perdas observadas em ensaios com um ...
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Papers by Alberto Colombo